A suspected breakaway faction from Greece’s neo-Nazi Golden Dawn party says it is recruiting anti-migrant hit squads and has vowed to drive all migrants and refugees out of Greece.

The group, naming itself Crypteia, after a vigilante band of ancient Spartans who terrorized slaves, told a Greek news outlet Tuesday, “We will fight until the last immigrant leaves. And to that end, we will use force and violence, mercilessly.”

Crypteia claimed responsibility for an attack Friday on the Athens home of an 11-year-old Afghan boy and his family, whose apartment was pelted by rocks and beer bottles. A note was left that read, “Go back to your village. Leave.”

The boy, Amir, had drawn local attention days before the attack after having been picked to carry the Greek national flag for his school in a national day parade, only to have the privilege revoked and given a school sign to hold instead.

“I was shouting and calling for help,” Amir’s mother told local reporters. “The children had woken up, crying; they were very afraid. The children's room was full of glass. A beer bottle was on the bed. The stones kept coming, one after the other. I panicked. I didn't know what to do,” she added.

Greek Prime Minister Alexis Tsipras condemned the attack, saying, “Amir, and every child in our country, deserves the right to security and Greek education, without discrimination.” State prosecutors have opened an investigation.

Europe has seen the emergence of other violent anti-migrant groups and a European Union agency reported in May 33 percent of Sub-Saharan Africans in Europe have been victims of at least one racially-motivated crime in the previous 12 months.

A network of civil rights activists, the European Network against Racism, warned recently that crimes against immigrants were under-reported and said minorities“are not targeted randomly by perpetrators.”

Recent opinion polls suggest anti-migrant sentiment is rising in Greece. The country has witnessed a surge in the past few months in the number of refugees and migrants entering the country, exacerbating already terrible living conditions in camps on the Greek islands and shelters on the mainland.

FILE - Stranded migrants and refugees hold placards as they protest outside the German Embassy in Athens.

Last month, officials said the number of people arriving, across land and sea borders, had more than doubled since June, with authorities estimating that arrivals are now at their highest level since March 2016, with more than 200 men, women and children being registered every day.

Refugee flows had dropped dramatically after a landmark accord was reached between the European Union and Turkey in March 2016. In return for aid Ankara agreed to strengthen border patrols along its Aegean coast and turn back smuggler boats.

How serious a threat Crypteia poses is the subject of debate within Greek political and police circles with some saying that invoking the ancient Spartan band is nothing more than cover for a bunch of crude thugs. Others are not so sure.

Stavros Theodorakis, leader of the centrist Potami party, complains that Greece is seeing a rise of serious political gang violence across the ideological spectrum, warning, “every day there is a new target. Gangs intimidate with impunity.”

FILE - Supporters of Greece's extreme right party Golden Dawn attend a rally commemorating a 1996 military incident which cost the lives of three Greek navy officers and brought Greece and Turkey to the brink of war, in Athens, on Saturday, Jan. 28, 2017.

Analysts say there has been talk within Golden Dawn circles of forming secretive anti-migrant hit squads since several party leaders and lawmakers were arrested following the 2013 murder of anti-fascist rapper Pavlos Fyssas by an alleged supporter of the party. Their trial is ongoing.

Greece has seen a wave of hostility towards the more than 60,000 migrants estimated to be in the country with shelters and refugee squats being targeted. Civil rights activists say far-right groups have been stoking local grievances and anti-refugee sentiments. Many attacks and assaults, they say, go unreported

Greece isn’t alone in being buffeted by anti-migrant violence. German authorities say there were more than 3,500 attacks against refugees and asylum shelters in 2016, amounting to nearly a dozen acts a day of anti-migrant violence, neo-Nazis have been blamed for many of the attacks.